Recombinant DNA technologies have offered a unique opportunity for scientists to produce essentially unlimited quantity of proteins of interest for therapeutic use and also for further research. Some difficulties however can seriously hinder the recombinant production of certain proteins, such as proteins of larger sizes and/or of limited solubility. For example, the BRCA2 protein has been the focus of intense research due to the involvement of this protein in various human epithelial cancers including breast and ovarian cancers, but efforts to recombinantly producing this protein has been largely unsuccessful. The present inventors devised a new strategy in the recombinant production of proteins and this new strategy has demonstrated unexpected effectiveness in improving the quantity of expression, solubility of the recombinant protein, and ease of purification of the protein. Their discovery is therefore a significant improvement, especially for certain proteins, such as the BRCA2 protein, which have the characteristics of relatively large size and low solubility, and which other researchers have previously been unable to recombinantly produce in desirable quantity and quality.